With the advent of an increasing number of multicast services such as audio/video streaming and news broadcast, accounting for the resources consumed by subscribers becomes essential. However, multicast environ­ments are inherently more susceptible to attacks. Although e-commerce protocols such as SSL, TLS, and SET protocols offer some forms of security, they cannot be directly applied to secure e-commerce sessions in the multi­cast environment. As secured multicast services gain popularity in the Internet, at one point there would be a significant response from the service providers to...